Bofors 40mm L70 experimental round

[tigbrand]

Hi chaps,have recently aquired a cracking 40/70 bofors round off a Bocn member. Im perplexed as to what it was for. It was originally painted white with a red band and stencilled 40/70 for fuse recovery. On the case and projectile is the code S1/1503/94 and case stencil EXPTL. Projectile is stamped RL 4/57. The round is near mint but missing paint and still crimped in. The nose cap unscrews to show a threaded hole for the fuse to go in. This is aprox 1 inch dia with a fine R/h thread. Anybody any ideas?? The code must relate to the project this was made for? Sorry no pics at the moment. Cheers Tony.

 

[Chris 42 RQ]

High Altitude recovery.

Tig I think you have answered your own question in as much as it was marked for "Fuze recovery".
At a guess it would be either water recovered (not the most reliable or safest method) or it would have been High altitude fired- ie Vertically fired and tracked by Radar and then dug up from its point of impact having come back down to earth in the same attitude as it went up-base down !
Deep hole to dig for a small object but one very good method of safe recovery to assess a fuzes function.

 

[SG500]

Wow what a great job firing shells up in the air and recovering them, sounds like a great thing to do (jealous!!).

Dave.

 

[tigbrand]

Bofors

Hi Chris,i understand the principle of what it was for,just thought there might be a way of identifying which trial it was used for,cheers Tig.

 

[Chris 42 RQ]

OB Reqn DD/L Numbers

Hi Tig, sadly without its unique reference number which may be one of many types ie DD/L or OB Reqn No there will be very little chance of ever finding out what was special about it other than it is an "Experimental" item and thats that-however, watch out as SG500 might be after it :hahaha:

Not forgetting Spotter either-he may need to get his Radar going and his shovel at the ready.

 

[tigbrand]

ID

Hi Chris i may have a lead! A member pm,ed me so you never know! This round is staying in my collection,as i now seem to have 9 rounds which is strange as i never collected bofors stuff,they must be breeding under the stairs! Cheers Tig:tinysmile_fatgrin_t

 

[2pounder]

vertical firing

Some while ago I visited a site on Salisbury Plain where they fired 4.5in Naval shell vertically to test fuzes. The shell comes back to earth base first and its position is spotted from two observation points and then they go out with a boring maching and dig down vertically beside the hole and recover the shell. Dont know if other rounds and fuzes are tested this way but it would make sense to do it but small stuff might be harder to find.
2pr

 

[SG500]

Hi Tig, sadly without its unique reference number which may be one of many types ie DD/L or OB Reqn No there will be very little chance of ever finding out what was special about it other than it is an "Experimental" item and thats that-however, watch out as SG500 might be after it :hahaha:

Well what can I say........that's exactly what I was thinking Chris!!

Dave.

 

[Chris 42 RQ]

Big and small.

Some while ago I visited a site on Salisbury Plain where they fired 4.5in Naval shell vertically to test fuzes. The shell comes back to earth base first and its position is spotted from two observation points and then they go out with a boring maching and dig down vertically beside the hole and recover the shell. Dont know if other rounds and fuzes are tested this way but it would make sense to do it but small stuff might be harder to find.
2pr

2 Pounder the site you mention does it with everything from 8 inch (in the past) down to 30mm and perhaps even a little smaller although I was told that the smaller stuff usually had to be fired in large numbers to make sure that at least one was found !
And at the time the tracking was both visual and by sophisticated Radar but tracking a 30 mm dropping back to earth from on very high is still a problem as it left very little "backwash" or none at all. ( Backwash is the plume of chalk thrown up from the hole the projectile makes.)

Tig pleased to hear you may have a lead as without documentation it is impossible to find out what was special with an item unless it was a very obvious modification.

SG500 well looks like Tig is going to hang on to that one !
Keep looking !

 

[Bonnex]

Tony,

I promised to look up the Parent No 94 for the S1 series. I found it as Tracer, Shell, No 29 which is the tracer for 17Pr, 77mm, 20Pr. It does not seem to connect with your 40mm job I'm afraid unless there is something about your projectile that makes you think otherwise.

Hi chaps,have recently aquired a cracking 40/70 bofors round off a Bocn member. Im perplexed as to what it was for. It was originally painted white with a red band and stencilled 40/70 for fuse recovery. On the case and projectile is the code S1/1503/94 and case stencil EXPTL. Projectile is stamped RL 4/57. The round is near mint but missing paint and still crimped in. The nose cap unscrews to show a threaded hole for the fuse to go in. This is aprox 1 inch dia with a fine R/h thread. Anybody any ideas?? The code must relate to the project this was made for? Sorry no pics at the moment. Cheers Tony.

 

[glevum]

Here is a picture of the round in question (centre) with one with the original paint on the left and a proof round on the right.

When I got them some one had painted them with trowel and I didn't realise they had the original paint underneath until I stripped the first...

 

[tigbrand]

pics

Cheers for the pics old chap,would still like to confirm the purpose of this. By the way,if you never got my pm,your box of bits will be with weasel when you visit.Tony.:tinysmile_fatgrin_t.

 

[christhurston]

That's a very interesting trio you have there,Will,I originally,only intended
to get myself a pair of the L70 and L60 Bofors because the case lengths
fitted nicely either side of a Hotchkiss 3pdr,and,between,a pair of 2pdr A/T
rounds.(symmetry seemed desirable!!!) I'm finding,though,that I'm adding more and more Bofors,as I keep coming across different types of projectile
It's easy to get diverted from the original plan,and there certainly seems
to be an unending supply of variations.

 

[glevum]

Thanks Tony. I didn't get your PM.

I wonder if a normal Bofors fuze would fit the experimental round under the cap? It would then be protected during flight and still see the same setback force and rotation as a normal 40/70 shell.

Do you have a fuze you can try in it? I don't unfortunately.

Will.

 

[tigbrand]

fuze

Hi Will,the bofors fuze has coarser threads,i shall dig out my thread guages and measure the Tpi and pitch,this might help id the original use,i expect you would be interested to know too. Best wishes and nice to see you on here a bit more ,liked the Bismark pics by the way,Tony.

 

[Chris 42 RQ]

Swedish Fuze thread.

Will the thread you are measuring will most likely be the Swedish pattern standard Fuze thread.
Sorry but have no details of what that is.

Very nice items though especially the centre one as it is a little unusual.

 

[glevum]

Chris,

The centre and left rounds are the same.

I posted this to show what Tony's one looked like with the original paint on it.

Will.

 

[Chris 42 RQ]

Superb item.

Sorry Will, was not reading the thread properly.
What an interesting item that is, I think you may well be correct that the cover is merely to protect the fuze during its rearward travel into the earth.

 

[r_faruk]

hello there,

I'm new here, and this is my first post. I must say that you site is fantastic. I managed to find some thing that i couldn't find anywhere.
I know that the last post was in 2009, but since my question is about 40 mm L70 bofors, i decided to ask here.

Does anyone have a measurements of a thread for fuzes used in 40 mm bofors ammunition.

 

[TimG]

Welcome,

The thread, I strongly suspect, is going to be dependent on area of manufacture i.e. Britain - Europe, etc. As far as I'm aware, we British used an Imperial thread on the fuze. I don't have my books to hand, but will check later.

TimG